PVHL8WN - Pilot operated, pressure reducing/relieving main stage with integral T-8A control cavity and drain to port 4

Part Number: PVHL8WN

Manufacturer: Sun Hydraulics

DESCRIPTION:

This valve is a 3-way, normally open modulating element, externally drained, that incorporates an integral pilot control cavity. The pilot control cavity will accept any T-8A pressure control cartridge. The valve reduces a high primary pressure at the inlet (port 2) to a constant reduced pressure at port 1, with a full flow relief function from port 1 to tank (port 3). The pilot cartridge's setting determines the difference in pressure between reduced pressure (port 1) and the drain (port 4). This valve is open in the transition from reducing to relieving which provides good pressure control and dynamic response at the expense of higher pilot flow in the deadheaded condition.

  • Maximum pressure at port 3 should be limited to 3000 psi (210 bar).
  • This valve has been optimized to work with the RBAP X**, RBAP L**, and RBAN electro-proportional pilot reliefs.
  • The transition from reducing to relieving is slightly open. The result is very good pressure control with oil consumption of about 0.1 gpm (0,4 L/min.). The relatively high pilot control flow is only a factor in a dead-headed condition.
  • Cartridges configured with EPDM seals are for use in systems with phosphate ester fluids. Exposure to petroleum based fluids, greases and lubricants will damage the seals.
  • Full reverse flow from reduced pressure (port 1) to inlet (port 2) may cause the main spool to close. If reverse free flow is required in the circuit, consider adding a separate check valve to the circuit.
  • Pilot operated valves exhibit very low dead-band transition between reducing and relieving modes.
  • Pilot operated valves exhibit exceptionally flat pressure/flow characteristics, are very stable and have low hysteresis.
  • Pressure on the drain (port 4) is directly additive to the valve setting at a 1:1 ratio and should not exceed 5000 psi (350 bar).
  • Maximum inlet pressure is determined by the bias spring. The D spring is tested with 2000 psi (140 bar) maximum differential pressure and the W spring is tested with 5000 psi (350 bar) maximum inlet pressure.
  • NOTE: With the -8 control option, the main stage valve should first be installed to the correct torque value. The T-8A pilot control valve should then be installed into the main stage valve to its required torque value.
  • The -8 control option allows the pilot control valve to be incorporated directly into the end of the relief cartridge via the T-8A cavity. These pilot control cartridges are sold separately and include electro-proportional, solenoid, air pilot, and hydraulic pilot operation. See Pilot Control Cartridges.
  • Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.

CavityT-23A
Series3
Capacity40 gpm160 L/min.
Maximum Operating Pressure5000 psi350 bar
Control Pilot Flow25 - 30 in³/min.0,40 - 0,50 L/min.
Pilot Control CavityT-8AT-8A
Pilot Control Valve Installation Torque20 - 25 lbf ft27 - 33 Nm
Pilot Control Valve Hex Size7/8 in.22,2 mm
Valve Hex Size1 1/4 in.31,8 mm
Valve Installation Torque150 - 160 lbf ft203 - 217 Nm
Model Weight1.30 lb0,60 kg
Seal kit - CartridgeViton: 990-023-006

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Notes:
  • Compound cartridge (pilot and main stage) assembly information is provided for reference only. Cartridges must be ordered separately and assembled at point of use.

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